Abstract:
During recent earthquakes, weaknesses in strength and ductility were encountered in vertical structural elements, particularly columns, despite the existence of strict regulations. Among these deficiencies are loss of stability, buckling, occurrence of major constraints and finally less ductility. The results of the surveys reveal many cases of inadequate, inappropriate or poorly constructed columns confinement. The present research is based on these findings by studying the response of reinforced concrete columns under different types of confinement under axial loading. After a synthesis of previous works and an analytical study, an experimental program was realized at the level of the Materials and Durability Laboratory of the After a synthesis of previous works, an analytical study taking into account various models of the behavior of high strength concrete columns, an experimental program was elaborated and realized at the Laboratoire Matériaux et Durabilité des Constructions of the Department of Civil Engineering, Université Frères Mentouri Constantine. The analytical study of the behavior of internally confined high-strength concrete was carried out by varying different parameters, such as: concrete strength, steel yielding strength, transverse reinforcement density / confined core, section shape, etc. Experimental results obtained by several researchers were collected and used in this analysis. The objectives sought by this study lie mainly in the evaluation of their influence on resistance and ductility gains. The flexural capacity of conventionally confined, high-strength concrete sections was discussed. After the equilibrium and deformation compatibility expressions of the studied section were established, a computer program in visual basic has been developed to carry out a parametric analysis which takes into account the same preceding factors. An experimental test campaign was carried out on several short columns specimens of self-compacting concrete subjected to uniaxial compression. In the first place tests were carried out on specimens of circular section conventionally confined with variables such as concrete strength and rate of transverse reinforcement. The second part concerned specimens confined externally by bonding CFRP-type composite fabrics. Finally, as an interesting contribution, not least, a third type of containment was discussed, that obtained by the use of PVC tubes, which were also used as formwork. The main goal of this experimental campaign is to evaluate the effect of confinement on the behavior of short columns under axial loading.
